The suit was disclosed by Clearstream’s parent firm, Deutsche Börse, in an announcement made on 18 January.

Bank Markazi is asking for $4.9bn plus interest, including $1.9bn paid to American plaintiffs following a 2013 US court order, and $2bn “which include assets that are held at Clearstream and which are currently subject to US and Luxembourg litigation brought by US plaintiffs,” Deutsche Börse said.

In its announcement, the company stated: “Clearstream believes the complaint against it to be without merit. Clearstream will take all necessary and appropriate measures to vigorously contest the claims.”